Human choriocarcinoma is being maintained in tissue culture and the modulation of two products (chorionic gonadotropin and placental alkaline phosphatase) which are tumor markers is being examined. The ability of BCG-activated macrophages to kill human choriocarcinoma is also being examined. BIBLIOGRAPHIC REFERENCES: Speeg, K.V., Azizkhan, J.C., and Stromberg, K.: The stimulation by methotrexate of human chorionic gonadotropin and placental alkaline phosphatase in cultured choriocarcinoma cells. Cancer Research 36: 4570-4576, 1976. Speeg, K.V., Azizkhan, J.C., and Stromberg, K.: Characteristics of alkaline phosphatase from two continuous lines of human choriocarcinoma cells. Experimental Cell Research 105: 199-206, 1977.